Dr F. von Hochstetter's first New Zealand geological publication described the Drury Coalfield. Coa! measures, at the base of the Te Kuiti Group, contain dirty thin coal seams, and only about 8,000 tons of sub-bituminous coal have been mined in 100 years. The measures are overlain conformably by Whaingaroan Mangakotuku Siltstone in the south, and unconformably by Otaian Waitemata Group (including Papakura Limestone) in the north. Following block faulting, basalt was extruded up fault planes.